stkbottom  equ  $8000
main       equ  $400
led        equ  $e003
isr4       equ  $a00
isr7       equ  $b00
isr3       equ  $c00
rst        equ  0
ilevel3    equ  $6c
ilevel4    equ  $70
ilevel7    equ  $7c


           org  rst
           dc.l stkbottom
           dc.l main

           org  ilevel3
           dc.l isr3

           org  ilevel4
           dc.l isr4

           org  ilevel7
           dc.l isr7




           org main   ; main program starts here
           move #$2300,sr   ;enable interrupt level 4 and upper
loop       bra loop
           nop





            org isr4
            movem.l d0,-(a7)
            move.b led,d0
            eor.b #$10,d0
            move.b d0,led
            movem.l (a7)+,d0
            rte

            org isr7
            movem.l d0,-(a7)
            move.b led,d0
            eor.b #$80,d0
            move.b d0,led
            movem.l (a7)+,d0
            rte


            org isr3
            movem.l d0,-(a7)
            move.b led,d0
            eor.b #$04,d0
            move.b d0,led
            movem.l (a7)+,d0
            rte


